Display devices such as, for example, flat panel display devices typically utilize an evacuated environment during operation. In a field emission-type display device, field emitters located on a cathode emit electrons which are directed towards respective pixel or sub-pixel regions on a faceplate. In such a device, it is imperative that the region between the faceplate and the cathode (i.e. the active environment) remain free of contaminants so that the electrons can travel unimpeded from the cathode to the faceplate. As yet another concern, if certain contaminants are present in the active environment between the cathode and the faceplate, certain features, such as the field emitters may be damaged.
With reference now to Prior Art FIG. 1, a side sectional view of a display device 100 employing a conventional contaminant reduction approach is shown. Specifically, Prior Art FIG. 1 shows a backplate or cathode 102 secured to a faceplate 104 via a sealing frame 106. The active environment is the region located between cathode 102 and faceplate 104. Field emitters, typically shown as 108, are coupled to cathode 102 and are disposed within the active environment. In the conventional approach of Prior Art FIG. 1, a getter material 110 is also coupled to the cathode and is disposed within the active environment. The getter material is intended to capture contaminant particles which remain in the active environment after an evacuation process. The getter material is also intended to capture contaminant particles which are generated during operation of display device 100.
Unfortunately, the conventional approach of Prior Art FIG. 1 has significant drawbacks associated therewith. By locating getter material 110 within the active environment, region 112 is no longer available for use. That is, such a prior art approach reduces or compromises the amount of space which is available to be utilized by features such as, for example, field emitters. Additionally, by placing getter material 110 within the active environment, such a prior art approach deleteriously subjects the active environment, and hence field emitters 108, to the hazardous getter material 110. As a result, field emitters 108 are often degraded or damaged due to their close proximity to getter material 110.
With reference now to Prior Art FIG. 2, a side sectional view of display device 100 employing another conventional approach in an attempt to reduce contaminants is shown. In this approach a pump-out tube is coupled directly to the active environment. The pump-out tube is used to facilitate evacuation of display device 100, and, hence, remove contaminants therefrom. Once again, such a conventional approach has severe drawbacks associated therewith. Attaching tubulation directly to the active environment of display device 100 greatly complicates the process of manufacturing display device 100. Additionally, the increased complexity associated with attaching the tubulation directly to display device 100 adds additional cost to the manufacturing process. Furthermore, the potential for defects in display device 100 is heightened by attaching tubulation 114 directly to display device 100.
Referring still to Prior Art FIG. 2, conventional tubulation such as tubulation 114 significantly alters and increase the “envelope” of display device 100. The envelope of display device 100 refers roughly to the amount of space occupied by the display device 100. In Prior Art FIG. 2, the envelope of display device 100 is shown by dotted line 116. As a result of protruding tubulation 114, display device 100 must be allotted a larger area in which to operate. It will be seen from Prior Art FIG. 2, that the increased area or envelope 116 required by tubulation 114 may restrict or limit the locations and environments in which display device 100 can be used.
With reference next to Prior Art FIG. 3, a side sectional view of display device 100 employing another conventional approach in an attempt to reduce contaminants is shown. In this conventional approach, tubulation 118 is again attached directly to the active environment of display device 100. As still another drawback, tubulation 118 extends beyond the edge of display device. As result, prior art tubulation 118 often interferes with the sealing process used to secure cathode 102 and faceplate 104 together. More specifically, during a laser sealing process, for example, the laser beam or beams must contact the entire periphery of display device 100. In the configuration shown in Prior Art FIG. 3, tubulation 118 can obstruct the laser beam or beams, thereby “shadowing” a portion of the periphery of display device 100. As a result, the seal between cathode 102 and faceplate 104 can be compromised, or the sealing process must be altered to accommodate tubulation 118.
Thus, a need exists for an apparatus which removes contaminants from a display device without compromising the usable amount of space available within the display device. A further need exists for an auxiliary chamber which meets the above listed needs but which does not deleteriously expose features of the display device to getter material. Still another need exists for an auxiliary chamber which meets the above-listed needs but which does not significantly increase or alter the overall dimensions of the display device. Still another need exists for an apparatus that has improved contaminant particle removal.